Just a thought, prompted by personal experience.
If possible find the bag, then send a certified letter with signature required and return verification (costly I know but worth it in the long run), give him a reasonable time frame to make arrangements pick it up (30 days is common) from a designated place at a designated time. Then when that time passes if it has not been removed it becomes yours to do with as you wish.
That was my lawyers advice many years ago in a similar situation. YMMV